Dual-frequency ultrasonic driving power supply and dual-frequency ultrasonic treatment device

Abstract

The utility model provides a kind of dual-frequency ultrasonic driving power supply and dual-frequency ultrasonic treatment equipment.Wherein, dual-frequency ultrasonic driving power supply, comprising: main control unit, for generating square wave signal;Main control unit has two output ends;Two drive units are connected with the two output ends of main control unit respectively;Two drive units are all used to adjust the power of square wave signal, and square wave signal is converted into sinusoidal signal;Matching unit has two matching channels;The input end of two matching channels is connected with the output end of two drive units respectively, and the output end is connected with the two input ends of dual-frequency ultrasonic transducer respectively.The utility model provides a kind of dual-frequency ultrasonic driving power supply avoids using linear amplification equipment, and the equipment cost and volume of dual-frequency ultrasonic driving power supply can be reduced.

Description

Technical Field

[0001] This utility model belongs to the field of ultrasonic equipment technology, specifically relating to a dual-frequency ultrasonic drive power supply and a dual-frequency ultrasonic therapy device. Background Technology

[0002] Ultrasound-Stimulated Acoustic Emission (USAE) is an imaging technique based on the principle of beat frequency generation through difference-frequency ultrasonic interferometry. This technique generates acoustic emission signals by inducing low-frequency vibrations in the target area of ​​tissue, thereby achieving acoustic spectrum imaging. In the implementation of this technique, the ultrasonic drive power supply is a key component of the ultrasonic therapy system, and its performance directly affects the overall effect of the system.

[0003] Currently, in ultrasound therapy applications requiring the driving of dual-frequency ultrasound transducers, the conventional solution is to use a signal generator to produce a driving signal, which is then amplified by two linear power amplifiers. However, as the output power increases, the size of the linear power amplifier equipment increases significantly, accompanied by a rise in noise levels. Furthermore, these high-power linear power amplifiers are often expensive, making them unsuitable for applications requiring high power output. These technical limitations severely restrict the further development and promotion of ultrasound-induced acoustic emission technology in clinical treatment and research applications. Utility Model Content

[0004] This invention aims to solve the problems of high cost and large footprint of existing dual-frequency ultrasound drive power supply equipment, and provides a dual-frequency ultrasound drive power supply and a dual-frequency ultrasound therapy device.

[0005] To achieve the above technical objectives, this utility model provides a dual-frequency ultrasonic driving power supply for driving a dual-frequency ultrasonic transducer, comprising: a main control unit for generating square wave signals; the main control unit has two output terminals;

[0006] Two drive units are respectively connected to the two output terminals of the main control unit; both drive units are used to adjust the power of the square wave signal and convert the square wave signal into a sine wave signal.

[0007] The matching unit has two matching channels; the input terminals of the two matching channels are respectively connected to the output terminals of the two driving units, and the output terminals are respectively connected to the two input terminals of the dual-frequency ultrasonic transducer.

[0008] Optionally, the dual-frequency ultrasonic drive power supply further includes: a sampling unit connected to the output terminals of the two drive units, used to acquire the sinusoidal wave signals output by the drive units and obtain the signal parameters of the acquired sinusoidal wave signals; the sampling unit is also communicatively connected to the main control unit;

[0009] The main control unit is also used to adjust the signal parameters of the square wave signal generated by the sampling unit according to the signal parameters of the sine wave signal obtained by the sampling unit.

[0010] Optionally, each of the driving units includes a power factor correction circuit, used to perform power factor correction on the received square wave signal so that the voltage phase and current phase of the square wave signal are consistent.

[0011] An adjustment module is connected to the power factor correction circuit; the adjustment module is used to output a compensation current to the power factor correction circuit to compensate for the harmonic components of the square wave signal processed by the power factor correction circuit.

[0012] A step-up / step-down circuit, connected to the output of the power factor correction circuit, is used to increase or decrease the voltage of the DC current.

[0013] An inverter circuit, connected to the output terminal of the buck-boost circuit, is used to convert the square wave signal into a sine wave signal.

[0014] Optionally, the adjustment module is also connected to the buck-boost circuit, and the main control unit is also communicatively connected to the buck-boost circuit; the main control unit is also used to control the buck-boost circuit to control the voltage rise or fall of the DC current according to the signal parameters of the sine wave signal.

[0015] Optionally, the adjustment module is also communicatively connected to the sampling unit and the inverter circuit;

[0016] The adjustment module is also used to send a control current to the inverter circuit according to the signal parameters of the sine wave signal obtained by the sampling unit and the preset target voltage, so as to control the rise or fall of the sine wave signal voltage output by the inverter circuit.

[0017] Optionally, the driving unit further includes a filtering circuit, which is connected to the main control unit and the power factor correction circuit respectively, for filtering noise signals in the signals transmitted by the main control unit and transmitting the filtered square wave signal to the power factor correction circuit.

[0018] Optionally, the drive unit further includes an isolation communication module connected between the main control unit and the adjustment module.

[0019] Optionally, the matching unit includes two matching circuits, both of which are configured to have variable circuit impedance.

[0020] The main control unit is also communicatively connected to the matching unit, and the main control unit is also used to adjust the circuit impedance of the two matching circuits according to the frequency of the sine wave signal collected by the sampling unit.

[0021] Optionally, the main control unit includes: a signal source module for generating two initial square wave signals;

[0022] A comparison module is used to compare the rising edge timing of the two initial square wave signals;

[0023] The frequency generation module is used to adjust the delay of at least one of the two initial square wave signals according to the comparison result obtained by the comparison module, so as to adjust the time difference between the two initial square wave signals.

[0024] As another solution, this utility model also provides a dual-frequency ultrasound therapy device, including a dual-frequency ultrasound drive power supply and a dual-frequency ultrasound transducer as described above; the dual-frequency ultrasound drive power supply is used to provide two sinusoidal signals for driving the dual-frequency ultrasound transducer.

[0025] The dual-frequency ultrasonic transducer includes two ultrasonic transducers, which are respectively connected to the two output terminals of the matching unit to convert the received sine wave signal into ultrasonic waves.

[0026] This utility model can achieve the following technical effects:

[0027] The dual-frequency ultrasonic drive power supply device proposed in this embodiment of the invention, by combining a main control unit for outputting square waves, a drive unit that can convert square waves into sine waves, and a matching unit that can match the impedance of the dual-frequency ultrasonic transducer, can realize the signal processing flow of "outputting square waves - signal conversion - matching output". Thus, it can use a low-cost square wave signal source and a small-sized and low-cost conversion unit, thereby effectively reducing equipment costs while meeting the high-intensity pulse signal requirements of the dual-frequency ultrasonic transducer. Attached Figure Description

[0028] Figure 1 A schematic diagram of a dual-frequency ultrasonic drive power supply provided for an embodiment of the utility model;

[0029] Figure 2 A schematic diagram of a drive unit provided in an embodiment of the utility model. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0032] It is understood that, without conflict, the various embodiments of this utility model and the features thereof can be combined with each other.

[0033] It is understood that, for ease of description, the accompanying drawings of this utility model only show the parts related to the embodiments of this utility model, while the parts unrelated to the embodiments of this utility model are not shown in the drawings.

[0034] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of the embodiments of this utility model may occur in a different order than that marked in the accompanying drawings.

[0035] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

[0036] In related technologies, dual-frequency ultrasound therapy devices typically employ two high-frequency sine wave signals of different frequencies to drive two sets or two ultrasound transducers, outputting ultrasonic signals with different frequencies. This allows for the use of difference-frequency ultrasonic interference to generate a beat frequency phenomenon at the convergence point of the two ultrasonic waves, inducing low-frequency vibrations in the target area tissue, resulting in acoustic emission and thus acoustic spectrum imaging. Furthermore, the driving power supply in these devices usually consists of two sine wave signal sources and two linear power amplifiers connected one-to-one with each source to amplify the power of the sine wave signals. However, linear power amplifiers utilize numerous transistors, capacitors, and inductors, resulting in complex circuitry and a large size, leading to high overall equipment cost and a large footprint. Moreover, because dual-frequency ultrasound therapy devices require high-frequency, high-power ultrasonic signals, correspondingly, they also require high-frequency, high-power sine wave signals. This necessitates high output power from the linear power amplifiers, further increasing their size and cost.

[0037] To address the aforementioned technical problems, this embodiment provides a dual-frequency ultrasonic driving power supply for driving a dual-frequency ultrasonic transducer, such as... Figure 1As shown, it includes a main control unit 1, two drive units 2, and a matching unit 3 connected in sequence.

[0038] The main control unit 1 generates a square wave signal and has two signal output terminals. Two drive units 2 are connected to the two signal output terminals of the main control unit 1, respectively. Both drive units 2 are used to adjust the power of the square wave signal and convert it into a sine wave signal. The matching unit 3 has two matching channels; the input terminals of the two matching channels are connected to the output terminals of the two drive units 2, respectively, and the output terminals are connected to the two input terminals of the dual-frequency ultrasonic transducer. This enables a "square wave output - conversion - matching output" processing flow, providing two sine wave signals to the dual-frequency ultrasonic transducer. Furthermore, based on the main control unit 1 capable of emitting square waves, this embodiment proposes a drive unit 2 to process the square wave signal, specifically performing power adjustment and inversion functions. The circuit structures for adjusting the square wave signal power and inverting the square wave signal are typically simpler and smaller in size. Therefore, compared to linear power amplifier devices, the drive unit 2 proposed in this embodiment can significantly reduce the device size and cost.

[0039] Furthermore, as mentioned above, the relevant technical solutions employ linear power amplifiers to linearly amplify the signal, thus requiring a sine wave signal source. Compared to signal sources that generate square waves, sine wave signal sources are more complex in structure, larger in size, and more expensive. Moreover, square wave signals are more suitable for scenarios requiring high-frequency signals.

[0040] As can be seen, the dual-frequency ultrasonic drive power supply proposed in this embodiment can significantly reduce the size and cost of the equipment, and can meet the high-intensity pulse signal requirements of the dual-frequency ultrasonic transducer. Linear power amplifiers cannot directly convert square waves into sine waves, thus requiring a sine wave signal source. However, sine wave signal sources are complex in structure and expensive. Therefore, compared to the linear power amplifiers used in related technologies, the dual-frequency ultrasonic drive power supply proposed in this embodiment uses a square wave signal source, resulting in lower equipment costs.

[0041] In some embodiments, the dual-frequency ultrasonic drive power supply further includes a sampling unit 4. The sampling unit 4 is connected to the output terminals of the two drive units 2, and is used to acquire the sinusoidal wave signals output by the drive units 2 and obtain the signal parameters of the acquired sinusoidal wave signals; the sampling unit 4 is also communicatively connected to the main control unit 1. The main control unit 1 is further used to adjust the signal parameters of the square wave signal it generates based on the signal parameters of the sinusoidal wave signals acquired by the sampling unit 4, thereby achieving negative feedback regulation of the square wave signal. For example, the main control unit 1 can adjust the frequency of the square wave signal it generates to decrease when the frequency of the acquired sinusoidal wave signal is too high, and adjust the frequency of the square wave signal it generates to increase when the frequency of the acquired sinusoidal wave signal is too low.

[0042] For example, the signal parameters collected by the sampling unit 4 may include various parameters such as signal voltage intensity, signal current intensity, and signal fault parameters, in order to obtain information such as the intensity of the collected sine wave signal and whether there is a fault.

[0043] In some embodiments, such as Figure 2 As shown, both drive units 2 include a power factor correction circuit 21, an adjustment module 22, a buck-boost circuit 23, and an inverter circuit 24. The power factor correction circuit 21 corrects the power factor of the received square wave signal to make the voltage and current phases of the square wave signal consistent, thus approximating a sine wave waveform, facilitating subsequent conversion of the square wave signal into a sine wave signal. The adjustment module 22 is connected to the power factor correction circuit 21. The adjustment module 22 works in conjunction with the power factor correction circuit 21, outputting a compensation current to the power factor correction circuit 21 to compensate for the harmonic components of the square wave signal processed by the power factor correction circuit 21. This compensates for the voltage phase of the square wave signal using the control current, actively matching the phase of the square wave voltage.

[0044] The step-up / step-down circuit 23 is connected to the output of the power factor correction circuit 21 and is used to regulate the rise or fall of the DC current voltage to adjust the voltage amplitude of the square wave signal, thereby adjusting the power of the square wave signal. The inverter circuit 24 is connected to the output of the step-up / step-down circuit 23 and is used to convert the square wave signal after voltage step-up / step-down into a sine wave signal to realize the conversion process of "voltage regulation first, then inversion", so that the processing object of the step-up / step-down circuit 23 is a square wave signal.

[0045] Specifically, the buck-boost circuit 23 currently used for processing square wave signals employs fewer switching devices (e.g., switching transistors) and lower-cost filtering devices (e.g., capacitors). In contrast, the topology of buck-boost circuits for processing sine wave signals is more complex, typically including at least a rectifier bridge circuit, a boost circuit, a buck circuit, a full-bridge inverter circuit, and a filter circuit. Therefore, buck-boost circuits for processing sine wave signals usually contain a large number of transistors, capacitors, and inductors, resulting in higher manufacturing costs and larger size. Furthermore, since the transistors in buck-boost circuits for processing sine wave signals need to operate in the linear region for extended periods, they generate significant heat during signal transmission, necessitating additional heat dissipation equipment. Therefore, compared to buck-boost circuits for processing sine wave signals, the buck-boost circuit 23 proposed in this embodiment effectively reduces costs.

[0046] Moreover, the standardization of square wave buck-boost circuit equipment is currently quite high. Therefore, the buck-boost circuit 23 in the above embodiment can use commercially available square wave buck-boost chips, such as the LM5175 chip, thereby further reducing design costs.

[0047] In some embodiments, the main control unit 1 is also communicatively connected to the buck-boost circuit 23. The main control unit 1 is also configured to control the buck-boost circuit 23 to control the DC current voltage to rise or fall according to the signal parameters of the sine wave signal, so as to increase or decrease the voltage amplitude of the square wave signal, and to control the specific amount of increase or decrease in the voltage amplitude of the square wave signal.

[0048] For example, the main control unit 1 can control the step-up / step-down circuit 23 to increase or decrease the voltage amplitude of the square wave signal by comparing the real-time acquired sine wave signal voltage with the target voltage, so that the voltage amplitude of the square wave signal approaches or equals the target voltage.

[0049] In some embodiments, the adjustment module 22 is also communicatively connected to the sampling unit 4 and the inverter circuit 24. Accordingly, the adjustment module 22 can receive the signal parameters of the sinusoidal signal acquired by the sampling unit 4, and can also send a control current to the inverter circuit 24. The adjustment module 22 is further configured to send a control current to the inverter circuit 24 based on the signal parameters of the sinusoidal signal acquired by the sampling unit 4 and a preset target voltage, thereby controlling the rise or fall of the sinusoidal signal voltage output by the inverter circuit 24. Specifically, the adjustment module 22 can compare the voltage of the real-time sampled sinusoidal signal with the target voltage, and then control the inverter circuit 24 to control the sinusoidal signal based on the comparison result, so that the voltage amplitude of the sinusoidal signal rises or falls, and control the specific amount of rise or fall in the voltage amplitude of the sinusoidal signal.

[0050] For example, the adjustment module 22 can employ a digital signal processor (DSP chip), which can perform filtering, convolution, multiplication, and other operations on digital signals, and directly output digital signals or analog signals based on the processing results. Furthermore, the DSP chip offers extremely fast digital signal processing speed. Specifically, the adjustment module 22 can include two DSP chips. One can be connected to the power factor correction circuit 21 and output a compensation current to the power factor correction circuit 21, utilizing the fast response advantage of the DSP chip to provide the corresponding compensation current to the power factor correction circuit 21 in a timely manner. The other DSP chip can be communicatively connected to the sampling unit 4 and the inverter circuit 24, and output the aforementioned control current to the inverter circuit 24, utilizing the fast response advantage of the DSP chip to control the inverter circuit 24 in a timely manner to adjust the rise and fall of the sinusoidal signal voltage.

[0051] In some embodiments, such as Figure 2 As shown, the drive unit 2 also includes an isolation communication module 26. The isolation communication module 26 is connected between the main control unit 1 and the adjustment module to isolate external interference signals such as static electricity, radio frequency fields, and electromagnetic wave signals during the transmission of signals between the main control unit 1 and the adjustment module 22, thereby ensuring the stability and accuracy of the control of the adjustment module 22 by the main control unit 1.

[0052] In some embodiments, such as Figure 2 As shown, the drive unit 2 also includes a filter circuit 25. The filter circuit 25 is connected to the main control unit 1 and the power factor correction circuit 21 respectively. It is used to filter out noise signals in the signals transmitted by the main control unit 1 and transmit the filtered square wave signal to the power factor correction circuit 21 to avoid the square wave signal to be processed entering the power factor correction circuit 21 containing too much noise signal, thereby avoiding noise signals in the sine wave signal finally output by the drive unit 2.

[0053] For example, the filter circuit 25 can be an electromagnetic compatibility circuit (EMC), which can isolate the signals in the circuit from the external electromagnetic environment.

[0054] In some embodiments, the matching unit 3 includes two matching circuits to perform impedance matching on the two sinusoidal signals respectively. Both matching circuits are configured with variable impedance, so that when the frequency of the sinusoidal signal changes, the circuit impedance can be adjusted to achieve impedance matching of the sinusoidal signal, thereby minimizing sinusoidal signal loss and increasing output power. The main control unit 1 is also communicatively connected to the matching unit 3, and the main control unit 1 is also used to adjust the circuit impedance of the two matching circuits according to the frequency of the sinusoidal signal acquired by the sampling unit 4.

[0055] For example, both matching circuits can be equipped with variable resistors, so that the circuit impedance of the matching circuit can be adjusted by changing the resistance value of the variable resistors. Correspondingly, the main control unit 1 can also be communicatively connected to the variable resistors in the matching circuits to control the resistance value of the variable resistors, thereby adjusting the circuit impedance of the corresponding matching circuit when the output signal power changes.

[0056] In some embodiments, the main control unit 1 includes a signal source module, a comparison module, and a frequency generation module. The signal source module generates two initial square wave signals. The comparison module compares the rising edge timing of the two initial square wave signals. The frequency generation module adjusts the delay of at least one of the two initial square wave signals based on the comparison result obtained by the comparison module, thereby adjusting the time difference between the two initial square wave signals. Thus, the main control unit 1 can have synchronous output mode and asynchronous output mode; in specific applications, the output mode of the main control unit 1 can be selected according to actual driving requirements. In the synchronous output mode, the main control unit 1 can generate two synchronous square wave signals. Moreover, the main control unit proposed in this embodiment can significantly improve the synchronicity of the signals output by the two output terminals by comparing the timing between the two square wave signals. Thus, after processing by the two drive units 2, two synchronous sine wave signals can be output. In the asynchronous output mode, the main control unit 1 can output two square wave signals with a time difference, and the time difference between the two square wave signals is a specified time difference. It can also adjust the time difference between the initial square wave signals according to the actual driving requirements, so that the time difference between the two sine wave signals output after processing by the two drive units 2 is a specified time difference. In this way, it can adapt to a variety of different driving requirements.

[0057] For example, the comparison module can also be used to compare the falling edge timing of two initial square wave signals.

[0058] For example, the main control unit 1 can be a field-programmable gate array (FPGA) circuit.

[0059] For example, the main control unit 1 may also include a dead-time protection module. The dead-time protection module can modulate the two initial square wave signals respectively, and can delay the corresponding initial square wave signal by adding a dead time to the corresponding initial square wave signal, thereby forming a time difference between the two initial square wave signals. After being processed by the two drive units 2, two sine wave signals with a time difference can be output respectively.

[0060] As another technical solution, this application also proposes a dual-frequency ultrasound therapy device, including a dual-frequency ultrasound drive power supply and a dual-frequency ultrasound transducer as described above. The dual-frequency ultrasound drive power supply provides two sinusoidal signals for driving the dual-frequency ultrasound transducer, thereby driving the transducer to output two ultrasonic signals. The dual-frequency ultrasound transducer includes two ultrasonic transducers, each connected to one of the two output terminals of the matching unit 3. Both ultrasonic transducers convert the received sinusoidal signals into ultrasonic waves.

[0061] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A dual-frequency ultrasonic drive power supply for driving a dual-frequency ultrasonic transducer, characterized in that, include: The main control unit is used to generate square wave signals; the main control unit has two output terminals. Two drive units are respectively connected to the two output terminals of the main control unit; both drive units are used to adjust the power of the square wave signal and convert the square wave signal into a sine wave signal. The matching unit has two matching channels; the input terminals of the two matching channels are respectively connected to the output terminals of the two driving units, and the output terminals are respectively connected to the two input terminals of the dual-frequency ultrasonic transducer.

2. The dual-frequency ultrasonic drive power supply according to claim 1, characterized in that, Also includes: A sampling unit, connected to the output terminals of the two driving units, is used to acquire the sinusoidal signals output by the driving units and obtain the signal parameters of the acquired sinusoidal signals; the sampling unit is also communicatively connected to the main control unit. The main control unit is also used to adjust the signal parameters of the square wave signal generated by the sampling unit according to the signal parameters of the sine wave signal obtained by the sampling unit.

3. The dual-frequency ultrasonic drive power supply according to claim 2, characterized in that, Each of the driving units includes: A power factor correction circuit is used to correct the power factor of the received square wave signal so that the voltage phase and current phase of the square wave signal are consistent. An adjustment module is connected to the power factor correction circuit; the adjustment module is used to output a compensation current to the power factor correction circuit to compensate for the harmonic components of the square wave signal processed by the power factor correction circuit. A step-up / step-down circuit, connected to the output of the power factor correction circuit, is used to increase or decrease the voltage of the DC current. An inverter circuit, connected to the output terminal of the buck-boost circuit, is used to convert the square wave signal into a sine wave signal.

4. The dual-frequency ultrasonic drive power supply according to claim 3, characterized in that, The main control unit is also communicatively connected to the buck-boost circuit; the main control unit is also used to control the buck-boost circuit to control the voltage rise or fall of the DC current according to the signal parameters of the sine wave signal.

5. The dual-frequency ultrasonic drive power supply according to claim 3, characterized in that, The adjustment module is also communicatively connected to the sampling unit and the inverter circuit; The adjustment module is also used to send a control current to the inverter circuit according to the signal parameters of the sine wave signal obtained by the sampling unit and the preset target voltage, so as to control the rise or fall of the sine wave signal voltage output by the inverter circuit.

6. The dual-frequency ultrasonic drive power supply according to claim 3, characterized in that, The drive unit further includes: The filtering circuit is connected to the main control unit and the power factor correction circuit respectively, and is used to filter out noise signals in the signals transmitted by the main control unit and transmit the filtered square wave signal to the power factor correction circuit.

7. The dual-frequency ultrasonic drive power supply according to claim 4, characterized in that, The drive unit further includes: An isolation communication module is connected between the main control unit and the adjustment module.

8. The dual-frequency ultrasonic drive power supply according to claim 4, characterized in that, The matching unit includes two matching circuits, both of which are configured with variable circuit impedance. The main control unit is also communicatively connected to the matching unit, and the main control unit is also used to adjust the circuit impedance of the two matching circuits according to the frequency of the sine wave signal collected by the sampling unit.

9. The dual-frequency ultrasonic drive power supply according to claim 2, characterized in that, The main control unit includes: The signal source module is used to generate two initial square wave signals; A comparison module is used to compare the rising edge timing of the two initial square wave signals; The frequency generation module is used to adjust the delay of at least one of the two initial square wave signals according to the comparison result obtained by the comparison module, so as to adjust the time difference between the two initial square wave signals.

10. A dual-frequency ultrasound therapy device, characterized in that, The invention includes a dual-frequency ultrasonic drive power supply and a dual-frequency ultrasonic transducer as described in any one of claims 1-9; the dual-frequency ultrasonic drive power supply is used to provide two sinusoidal signals for driving the dual-frequency ultrasonic transducer. The dual-frequency ultrasonic transducer includes two ultrasonic transducers, which are respectively connected to the two output terminals of the matching unit to convert the received sine wave signal into ultrasonic waves.

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